I hope I'm not beating a dead horse with these hop spider designs, but I thought I'd share mine for any who were looking looking for a large diameter hop spider that's all stainless, maximizes utilization, and best of all, is CHEAP!
*4.5 in angle grinder with metal cutout wheel and sanding disc
*Nylon bags -3 bucks at any hardware store
*Two SS worm clamps (I had to use a 7in and 4in combination to get the required diameter.) - 5 bucks at Lowe's
*Thin gauge stainless steel pot. The one I got was 16 qt. and about 10.5in in diameter. $12 at Walmart, not too shabby. http://www.walmart.com/ip/Mainstays-16-Quart-Stock-Pot/20713638
*3 1/4 SS Bolts, nuts, and washers (unless you're lucky like me and your pot seats perfectly into your keggle's cutout)
*Step bit or metal bits if you need to make legs
I already had the grinder equipment and didn't need the bolts, so my total bill was only 17 bucks.
I set up the angle grinder to cut out the bottom half of the pot. This is a pretty easy job if you keep the grinder on a block and rotate the pot.
Cutting and deburring the pot took less than about 10 minutes.
I've heard issues about the nylon bags falling out with a heavy hop load, even when it's clamped down. I don't expect this to be a problem with this design because at this diameter the bag is under some natural tension (it took some working around the edges to get the bag to stretch over the ring.) I'd avoid doing this design with any diameters larger than 10.5 inches.
... With the handles, it fits perfectly in my keggle (and hopefully yours.) Best part, the bag just barely touches the bottom of the keg.
I'm going to test this out this weekend on a worst case scenario batch: Pliny clone, LOTS of pellet hops, and a plate chiller. From what I've read on other threads there's not really a need for any additional filtration or to whirlpool. However, please feel free to call me out if you think I'll run into problems.
By the way, I've been lurking on this site for over a year and a half now, and this is my very first [legitimate] post. So a big "thank you" to all of you out there for taking the time to share your knowledge with the rest of us. Cheers!